Conventional zooming objective lenses used so far on endoscopes embrace the following types.
Type 1
This type is designed to vary magnification with the endoscope body in proximity to the object of interest, and has general applications. One example of implementing proximity magnifications by varying working distances (WD) is set forth in Patent Publication 1.
Type 2
This type is designed to implement zooming in a constant working distance (WD), as set forth typically in Patent Publication 2.
Type 3
This type is designed to implement zooming in a constant working distance and implement proximity magnification while the working distance (WD) is varied, as set forth typically in Patent Publication 3.
In applications other than the endoscopes, on the other hand, video cameras are widely known as equipment having zooming capabilities. A typical example of the objective lens for video cameras is set forth in Patent Publication 4.
Electronic magnification capable of electronically magnifying images is widely known as means without recourse to optical zooming.